Diffuse Reflection

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Diffuse Reflection

When a light beam interacts with a material it may be reflected into many directions, depending on the properties of the material. This type of interaction is called diffuse reflection . This normally happens when light hits a rough surface/material. Look at the example of diffuse reflection in Figure 3.6.

Figure 3.6. Diffuse reflection.

Now most books don't show what really happens when the light hits the material. So let's zoom in on the surface and take a closer look at the new random directions generated off the diffuse surfacesee Figure 3.7. The basic law of reflection still is applied to each ray on the diffuse surface. It doesn't seem this way because you can't really see the tiny simple reflections that occur. The different reflected angles on the rough surface cause reflections in many directions.

Figure 3.7. Microscopic view of the reflected random directions based on a material's impurities.

This is called microfacet surface roughness where a rough surface has very small mirror-like faces, where each tiny mirror has its own orientation for reflecting a beam of light to simulate roughness on the surface.

NOTE

NOTE

When light hits some materials,most of the time the light waves enter the material and scatter around a bit before they emit from the material from some arbitrary direction.You will not be using this idea when you simulate diffuse reflection.You'll simulate light being reflected from the point of interaction on the material.The reason why you don't use this method is because it's too compli cated and takes up too much time when rendering.

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